Determination of the eutectic composition by crystal growth and flux separation: example BaCuO2−CuOx
1991; Elsevier BV; Volume: 112; Issue: 2-3 Linguagem: Inglês
10.1016/0022-0248(91)90342-3
ISSN1873-5002
AutoresF. Licci, Hans J. Scheel, P. Tissot,
Tópico(s)Solidification and crystal growth phenomena
ResumoThe BaCuO2−CuOx phase diagram is of interest for synthesis and crystallization of the yttarium barium cuprate high-temperature superconductors and the thallium barium calcium cuprates. In this system there are difficulties in detecting the liquids temperatures by DTA, and the microscopic study of the sequence of crystallization is impeded by the opaqueness of the crystalline phases BaCuO2 and CuO. The problem of the determination of the eutectic composition could be solved by crystal growth and flux separation above the eutectic temperature, by identification of the crystals, and by annealing experiments. The eutectic was found at 29±1.5 mol% BaO and 910 ± 10°C in air, and at 33 ± 3 mol% BaO and 930 ± 10°C in oxygen atmosphere.
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